pot metal

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A copper and lead alloy, formerly used in making plumbing fixtures.
• noun A cast iron used especially in making pots.
• noun An inexpensive alloy of poor quality, usually containing lead, used especially in making castings.
• noun Glass melted in a pot.
• noun Glass colored by being mixed with melted stained glass in a pot.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun cast iron used for making cooking wares
• noun an alloy of copper and lead used especially for making large pots